## 题目描述 给定一个字符串 s 和一个字符串字典 wordDict ，在字符串 s 中增加空格来构建一个句子，使得句子中所有的单词都在词典中。以任意顺序 返回所有这些可能的句子。 注意：词典中的同一个单词可能在分段中被重复使用多次。 ## 示例 **示例 1:** **输入:** s = "catsanddog", wordDict = ["cat","cats","and","sand","dog"] **输出:** ["cats and dog","cat sand dog"] **示例 2:** **输入:** s = "pineapplepenapple", wordDict = ["apple","pen","applepen","pine","pineapple"] **输出:** ["pine apple pen apple","pineapple pen apple","pine applepen apple"] **解释:** 注意你可以重复使用字典中的单词。 **示例 3:** **输入:** s = "catsandog", wordDict = ["cats","dog","sand","and","cat"] **输出:** [] ## 约束条件 1 <= s.length <= 20 1 <= wordDict.length <= 1000 1 <= wordDict[i].length <= 10 s 和 wordDict[i] 仅有小写英文字母组成 wordDict 中所有字符串都 不同 ## LeetCode 链接 https://leetcode.cn/problems/word-break-ii/